Raspberries and Blackberry canes

Hi wee Q or 2 for you you helpful people
So i am planning on buying 2 canes of raspberries (1 polka and 1 all gold) and 2 black berry (loch Ness and Karaka black). I am planning on growing them along a 6ft fence, i have so far dug a trench into VERY stoney ground that weeds were struggling to get through and filled it with compost, it's just over a ft deep. n' about 40cm wide, which will have a walled up bit to give it more depth. (not sure of length mayb just under 5ft long?)
Questions:
How deep do raspberry and blackberry canes like to be?
Is it a good or bad idea to grow summer & Autumn beside one another?
How far apart do they need to be from one another?
I have read the summer requires support while Autumn doesn't, would i have to physically tie the sumer up all the time or would it "grab" onto the fencing itself? (also does the autumn one need to be tied up as well?
Thank you once again for your help, you lot are teaching me so much!
Posts
Thank you very Much PansyFace, I will grow a blackberry at either side. Also i'm glad that they will root without a problem,
-Is it best to leave a good bit of space between each cane?
-would 5ft be enought space for 4 canes? so would have maybe a ft between each at most.
-Maybe i'd be best with one blackberry and one raspberry? if they fill any gap and then some...(i'm maybe trying to take on to much again lol)
Thanks again for all the advice, i really appreciate it.